T helper type 9 (TH9) cells are a recently described distinct subpopulation of CD4+ effector T-cells which are producing selectively and transiently interleukin-9 and are involved in pathogen immunity and immune-mediated diseases. After their discovery some articles were published with the aim to explore the abilities of this cell type, but many properties remain still unknown. Some studies are mutually contradictory concerning the relevant factors for TH9 cell development and less is known about the presence of this cell type in healthy human skin compared to diseased skin. Especially the time point at which TH9 cells are immigrating/differentiating in human skin remained completely unexplored. Therefore, the aim of this bachelor thesis was, to find out more about the presence of TH9 cells in human skin in early stages of the human life cycle, applying immunofluorescence stainings on human foreskin samples of different age groups. Additionally the differences with regard to TH9 cells between healthy and diseased human skin were investigated. Furthermore, the question was addressed, whether the isolation of TH9 cells and their in vitro cultivation is possible, using an established in vitro skin organ culture system. This study opens new possibilities and directions to explore that multifaceted T-cell type.